Flavouring composition

ABSTRACT

A flavouring composition for a minced-fish product which includes from 0.1 to 30 wt % of dimethyl sulphide, based on the total weight of the flavouring composition, and a cellulose ether derivative, wherein the weight ratio of dimethyl sulphide to cellulose ether derivative is 8:1 or less and the cellulose ether derivative which includes at least 2.5% by weight of hydroxyalkyl substituents.

TECHNICAL FIELD

The present invention relates to a flavouring composition and moreparticularly relates to a flavouring composition comprising dimethylsulphide and a cellulose ether derivative.

BACKGROUND AND PRIOR ART

Frozen minced fish, which is commonly referred to as “frozen surimi”, istypically produced by the process in which fish meat, such as pollack,is firstly minced, the minced fish is subjected to two or more washeswith fresh water to remove undesirable fish odours, a small amount ofcommon salt is added to the fresh water in the final wash step, the skinis removed where necessary, a screw-press is used to remove water fromthe product, sugars or sugar alcohols are mixed with the dried productand, finally, the product is packed and stored under refrigeration at−20° C. to −40° C.

One problem with this process is that the repeated washing steps removenot only undesirable flavours but also many of the desirable flavours.Therefore, replacement flavours must typically be added back into thesurimi to achieve the desired flavour profile.

Flavour compositions that can be used for adding back the desiredflavour profile contain dimethyl sulphide (referred to herein as “DMS”)as a major component because it delivers a desirable sulphury, vegetal,crab-like top note.

However, DMS is a volatile component that evaporates undesirably quicklyupon storage such that product containing it lose a significant part ofthe crab-like tope note.

Additionally, DMS is often incompatible with various other ingredientsused for adding back flavour into surimi products. This results in thepresence of an undesirable film, comprising the DMS, which is visible onthe surface of the flavour composition.

One approach to stabilize DMS in surimi products is to generate anemulsion of the DMS, which is hydrophobic, with certain hydrophilicingredients. However, emulsions are intrinsically unstable, especiallyupon storage over longer periods and/or at elevated temperatures and,once the emulsion separates, the known problems identified above canrecur.

Furthermore, emulsion manufacture is often an expensive andtime-consuming process requiring harsh processing conditions, such ashigh pressure, high shear or both. This is undesirable since the largeamount of heat generated by such processing risks driving off thevolatile DMS component.

Thus, it is an objective of the present invention to address one or moreof the abovementioned problems and/or to provide one or more consumerdesirable benefits.

We have now found that the addition of certain cellulose etherderivatives at the correct dosage can address one or more of theseproblems.

The use of hydroxypropyl methyl cellulose has been described in “Surimiand Surimi Seafood”, Second Edition by Jae W. Park, publisher: FoodScience and Technology) as an ingredient which can improve the textureof surimi. However, this requires very high levels of the ingredient. Inthe present invention, much lower levels of the cellulose etherderivative are required in order to stabilise the flavouring compositioncomprising DMS.

In U.S. Pat. No. 5,958,502 (Fulger et al), there is described a processfor incorporating a volatile component into a matrix. The volatilecomponent can be any component having a low boiling point, such as DMSand the matrix can be selected from a large number of materials,including cellulose ether derivative. The product is a glassycarbohydrate matrix and there is no disclosure or suggestion of usingDMS together with a specific cellulose ether derivative.

In Pangborn R M et al., Journal of Texture Studies, vol. 4, No. 4, 1974,pages 467 to 482, table 1 on page 468 discloses a compositioncomprising, amongst other ingredients, DMS and hydroxpropylcellulose.The amount of DMS is at most 0.0006 g/100 ml water, which is far belowthe amount used according to the present invention.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a flavouring composition fora minced-fish product comprising:

-   -   (a) 0.1 to 30 wt % of dimethyl sulphide, based on the total        weight of the flavouring composition, and    -   (b) a cellulose ether derivative,        wherein the weight ratio of (a) to (b) is 8:1 or less and the        cellulose ether derivative comprises at least 2.5% by weight of        hydroxyalkyl substituents.

The invention further provides a minced-fish product comprising theflavouring composition.

In a further aspect, the invention provides the use of a cellulose etherderivative in a flavouring composition comprising dimethyl sulphide tostabilise the composition.

In yet another aspect, the invention provides a process for thepreparation of a stable flavouring composition comprising the step ofmixing:

-   -   (a) from 0.1 to 30 wt % based on the total weight of the        flavouring composition of dimethyl sulphide together with    -   (b) a cellulose ether derivative comprising at least 2.5% by        weight of hydroxyalkyl substituents,        wherein the weight ratio of (a) to (b) is 8:1 or less.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a flavouring composition comprisingDMS.

DMS is a flavouring ingredient of formula (CH₂)₂S that, together withother seafood flavouring ingredients, is used in minced-fish products toprovide a characteristic sea-food aroma and taste.

It is a volatile compound having a boiling point of 83° C. and iseffective at delivering the desired aroma in minced-fish products, evenat very low levels. However, when present in amounts significantly abovethe threshold detection level, it is undesirably pungent. For thisreason, it is vital that the amount of DMS does not exceed 30 wt %,based on the total weight of the flavouring composition. Preferably, theamount of DMS is from 0.1 to 15 wt %, more preferably from 0.5 to 12 wt%, most preferably from 1 to 8 wt % based on the total weight of theflavouring composition.

Cellulose Ether Derivative

The flavouring composition of the invention comprises a small quantityof a cellulose ether derivative. It has been found that this materialstabilises the dimethyl sulphide in the composition in spite of theincompatibility of DMS with other flavouring components. It is believedthat the DMS is typically unstable because of the aqueous environment ofthe flavour composition and that the cellulose ether derivativestabilises the DMS by encouraging emulsification to provide, in thedispersed phase, the DMS. The continuous phase is thus aqueous,typically comprising the water-soluble flavour components.

Surprisingly, unlike other emulsion aids, the cellulose ether derivativeachieves stability over a long period. For instance, lecithin can beused to form an emulsion of DMS but the emulsion is typically observedto coalesce after only 24 hours storage at 20° C.

The cellulose ether derivative is preferably a hydroxy alkyl cellulosecomprising one or more pendant alkyl groups.

Preferred alkyl groups include C1 to C₅, more preferably C₂ to C₄ alkylchains. The alkyl chain may be branched or unbranched.

The percentage by weight of hydroxyalkyl substituent is preferablygreater than 2.5, more preferably from 3 to 20, more preferably from 4to 18, most preferably from 5 to 15%, e.g. from 7 to 12%.

It has been found that where the amount of hydroxyalkyl substituent isbelow 2.5 wt %, a less stable DMS emulsion is formed. For this reason,the cellulose ether derivative is not methyl cellulose since thismaterial has been found not to provide the desired emulsioncharacteristics.

It has been found through experimentation that hydroxyalkyl methylcellulose is highly preferred since the DMS emulsions formed using thismaterial are highly stable even upon long term storage at elevatedtemperatures. Most preferably, the alkyl group is a propyl moiety.

Where the cellulose ether derivative is hydroxyalkyl methyl cellulose,the percentage by weight of methoxyl substituent is preferably greaterthan 25, more preferably it is from 25 to 35, even more preferably from26 to 34, most preferably from 28 to 30.

The modified cellulose is preferably present in an amount of from 1 to20 wt %, more preferably from 1 to 15 wt %, most preferably from 1 to 7wt %, e.g. 1 to 4 wt %, based on the total weight of the flavouringcomposition.

Surprisingly, at these very low levels excellent retention of DMS isachieved. Advantageously, due to the high retention level upon storageachieved in this composition, the higher amounts of DMS conventionallyrequired to compensate for the evaporation of the DMS during storage areno longer required. Moreover, such levels are found to deliver anoverpowering sulphury note undesirable to consumers. Thus, theincorporation of a small amount of the cellulose ether derivative alsoenables a significant reduction in the amount of DMS required.

In order to provide an excellent emulsion, the weight ratio of DMS tocellulose ether derivative is preferably 8:1 or less, more preferably inthe range of from 1:2 to 8:1, even more preferably from 1:1 to 5:1, mostpreferably from 2:1 to 4:1.

When the weight ratio is above 8:1, it is found that the emulsified DMSdoes not remain stable upon storage.

Below about 1:2, the viscosity of the mixture is extremely high and issignificantly more difficult to process, for instance, pumping themixture becomes problematic.

Thus, it is preferred that the viscosity of the flavouring compositionis less than 1800 mPa·s at 100 s⁻¹ and 20° C.

It has also been found that if the viscosity of the flavouringcomposition is too low, the risk of creaming of the droplets of DMSincreases. Therefore, the viscosity should be sufficient to avoid this.Accordingly, it is preferred that the viscosity of the flavouringcomposition is greater than 900 mPa·s at 100 s⁻¹ and 20° C.

Other Ingredients

The flavouring composition typically comprises additional flavouringingredients suitable for use in an aqueous medium and for providingcrab-like notes. For instance, fish paste or shrimp paste are well knowningredients suitable for use in a minced-fish product.

Salt, especially sodium chloride, is typically added to the flavourcomposition. The amount of salt present should generally be less than 1%by weight based on the total weight of the flavour composition, morepreferably less than 0.7%. It has been found that the presence of saltreduces the solubility of the cellulose ether derivative and soadversely affects its ability to stabilise the DMS.

In order to improve emulsification, a solvent, especially an alcohol,can be in the composition. Particularly preferred are ethanol and/orpropylene glycol. Typically these can be used in an amount of from 5 to50% by weight based on the total weight of the flavouring composition,more preferably from 10 to 35%, most preferably from 20 to 30%.

The invention will now be described with reference to the followingexamples. It is to be understood that the examples are illustrative ofthe invention and that the scope of the invention is not limitedthereto.

All amounts are % by weight unless otherwise indicated.

EXAMPLES Example 1 Preparation of Crab Flavour Using Lecithin

A crab flavour was prepared by shearing together the followingingredients at 60° C. until the product appeared homogenous.

TABLE 1 Ingredient Amount (wt %) Crab topnote* 12.0 Lecithin 0.5 Ethanol5.0 Glycerin 40.0 Shrimp paste 5.0 Crab paste 5.0 Xanthan gum 0.12Propylene glycol 9.05 Water 23.3 *58.3% DMS, 34.8% ethanol, 6.9%propylene glycol

The composition was stored at 20° C. After 24 hours, a film of DMS wasvisible on the surface of the flavour. This demonstrates that the DMScomponent of the flavour is unstable when emulsified using aconventional emulsification agent.

Example 2 Preparation of a Crab Flavour Containing a Cellulose EtherDerivative

Various crab flavours were prepared using cellulose ether derivativesgiven in the table below.

TABLE 2 Cellulose Ether Derivative % methoxyl % hydroxypropyl Grade A*27.5-31.5 0 Grade E* 28.0-30.0 7.0-12.0 Grade K* 19.0-24.0 7.0-12.0*Methocel ® (ex Dow Chemicals)

Each cellulose ether derivative was incorporated into the followingflavouring composition:

TABLE 3 Ingredient Composition 1 (wt %) Composition 2 (wt %) Crabtopnote* 12 12 Crab paste** 5 — Shrimp paste** — 5 Propylene glycol 2525 Cellulose ether derivative*** 1.5 1.5 Citric acid 0.2 0.2 Water 51.351.3 *see table 1 **72% crab or shrimp seafood liquid flavourrespectively, 10% salt and 18% native tapioca starch ***grade A, E or Krespectively

The compositions were prepared by firstly dispersing the cellulose etherderivative in the propylene glycol. The water was then added withstirring until the cellulose ether derivative had completely dissolved,after which the citric acid was incorporated. The crab topnote was thenadded with further stirring followed by the crab paste or shrimp paste.The mixture was stirred until a homogeneous solution formed. All mixingwas performed under very low shear conditions and at room temperature.

The resulting flavour compositions were stored at room temperature for 1week, after which time the stability of the compositions was observed.The results are given in the following table.

TABLE 4 Composition 1 Composition 2 Grade A Film visible on surface Filmvisible on surface Grade E Stable/no film Stable/no film Grade K Filmvisible on surface Film visible on surface

Example 3 Effect of Varying the Amount of Cellulose Ether Derivative

A crab flavour according to composition 1 in table 3 was prepared usinggrade E except that the cellulose ether level was 0.8% and the propyleneglycol level was 25.7%.

The composition formed a cream layer upon storage demonstrating that theweight ratio of DMS to cellulose ether should be about 8:1 or less.

The results demonstrate that the compositions according to the inventioncan be prepared simply and inexpensively and avoid the need for harshprocessing conditions.

What is claimed is:
 1. A flavouring composition for a minced-fishproduct comprising: (a) 0.1 to 30 wt % of dimethyl sulphide, based onthe total weight of the flavouring composition, and (b) a celluloseether derivative comprising at least 2.5% by weight of hydroxyalkylsubstituents; wherein components (a) and (b) are present in a the weightratio of (a):(b) of 8:1 or less.
 2. The composition of claim 1, whereinthe cellulose ether derivative is a hydroxyalkyl methyl cellulose. 3.The composition of claim 2, wherein the cellulose ether derivative ishydroxypropyl methyl cellulose.
 4. The composition of claim 2, whereinthe hydroxyalkyl methyl cellulose comprises from 25% to 35% by weight ofmethoxyl substituents.
 5. The composition of claim 1, wherein the weightratio of components (a) to (b) is from 1:2 to 6:1.
 6. The composition ofclaim 1, in the form of an emulsion and further wherein the dimethylsulphide is in the dispersed phase.
 7. The composition of claim 1,wherein the composition comprises less than 1% by weight, based on thetotal weight of the flavouring composition, of sodium chloride.
 8. Thecomposition of claim 1, having a viscosity of between 900 and 1800 mPa·sat 100 s⁻¹ and 20° C.
 9. A minced-fish product comprising minced fishand the aqueous flavouring composition of claim
 1. 10. In a flavouringcomposition that includes dimethyl sulphide in an amount of from 0.1 to30 wt % based on the total weight of the flavouring composition, theimprovement which comprises stabilising the composition by providing acellulose ether derivative having at least 2.5% by weight ofhydroxyalkyl substituents in a weight ratio of dimethyl sulphide tocellulose ether derivative of 8:1 or less.
 11. A process for thepreparation of a stable flavouring composition comprising the step ofmixing: from 0.1 to 30 wt % based on the total weight of the flavouringcomposition of dimethyl sulphide together with a cellulose etherderivative comprising at least 2.5% by weight of hydroxyalkylsubstituents, wherein components (a) and (b) are present in a the weightratio of (a):(b) of 8:1 or less.